The invention relates to a composite thermal insulation system, particularly for installation on a building wall, which includes a light-absorbing outer wall surface, an at least partially light-transmissive thermal insulation material, and a largely light-transmissive coating on the outside.
In a known composite thermal insulation system of this type European Patent Document EP 0 333 145A1 corresponding to U.S. Pat. No. 5,016,412 to the same applicant (incorporated herein by reference), the disadvantageous fact of frequent overheating of the rooms in the summer has been demonstrated. This is surprising, because in the summer months the sun shines on the wall at a substantially steeper (less favorable) angle, and it might have been expected that overall, a smaller quantity of radiant energy would be converted. Measurements have shown that the composite thermal insulation system has a light transmission that is dependent on the position of the sun; specifically, for the critical noontime hours in the summer months, because of the angle of the sunshine prevailing then, the light transmission drops to approximately 25 to 30%. This natural angular dependency of the transparent thermal insulation system provides a certain self-protection in the summer months. Naturally, this applies to arbitrary other locations on the globe as well. Approximately at the Equator, although the climate is warmer, the angle at which the sun shines becomes all the steeper. As the distance from the Equator increases, the climate is colder by comparison, but in that case the sunshine is at a more favorable angle in terms of radiation.
Surprisingly, it has now been discovered that this angular dependency of the transparent thermal insulation system can be varied in a favorable way by the embodiment of the outer light-transmissive coating.